Method and device for treatment of mitral insufficiency

ABSTRACT

A device for treatment of mitral annulus dilation is disclosed, wherein the device comprises two states. In a first of these states the device is insertable into the coronary sinus and has a shape of the coronary sinus. When positioned in the coronary sinus, the device is transferable to the second state assuming a reduced radius of curvature, whereby the radius of curvature of the coronary sinus and the radius of curvature as well as the circumference of the mitral annulus is reduced.

REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/329,720, filed Dec. 24, 2002 now U.S. Pat. No. 6,997,931,which is a continuation-in-part of U.S. patent application Ser. No.09/775,677, filed Feb. 5, 2001 now U.S. Pat. No. 7,192,442, which is acontinuation-in-part of U.S. patent application Ser. No. 09/345,475,filed Jun. 30, 1999, now U.S. Pat. No. 6,210,432. U.S. patentapplication Ser. No. 10/329,720 also claims the benefit under 35 U.S.C.§119 to U.S. provisional application Ser. No. 60/344,121, filed Dec. 28,2001. Each of the referenced applications is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a device for treatment of mitralinsufficiency and, more specifically, for treatment of dilation of themitral annulus.

BACKGROUND OF THE INVENTION

Mitral insufficiency can result from several causes, such as ischemicdisease, degenerative disease of the mitral apparatus, rheumatic fever,endocarditis, congenital heart disease and cardiomyopathy. The fourmajor structural components of the mitral valve are the annulus, the twoleaflets, the chordae and the papillary muscles. Any one or all of thesein different combinations may be injured and create insufficiency.Annular dilation is a major component in the pathology of mitralinsufficiency regardless of cause. Moreover, many patients have a mitralinsufficiency primarily or exclusively due to posterior annulardilation, since the annulus of the anterior leaflet does not dilatebecause it is anchored to the fibrous skeleton of the base of the heart.

Studies of the natural history of mitral insufficiency have found thattotally asymptomatic patients with severe mitral insufficiency usuallyprogress to severe disability within five years. Currently, thetreatment consists of either mitral valve replacements or repair, bothmethods requiring open heart surgery. Replacement can be performed witheither mechanical or biological valves.

The mechanical valve carries the risk of thromboembolism and requiresanticoagulation, with all its potential hazards, whereas biologicalprostheses suffer from limited durability. Another hazard withreplacement is the risk of endocarditis. These risks and other valverelated complications are greatly diminished with valve repair.

Mitral valve repair theoretically is possible if an essentially normalanterior leaflet is present. The basic four techniques of repair includethe use of an annuloplasty ring, quadrangular segmental resection ofdiseased posterior leaflet, shortening of elongated chordae, andtransposition of posterior leaflet chordae to the anterior leaflet.

Annuloplasty rings are needed to achieve a durable reduction of theannular dilation. All the common rings are sutured along the posteriormitral leaflet adjacent to the mitral annulus in the left atrium. TheDuran ring encircles the valve completely, whereas the others are opentowards the anterior leaflet. The ring can either be rigid, like theoriginal Carpentier ring, or flexible but non-elastic, like the Duranring or the Cosgrove-Edwards ring.

Effective treatment of mitral insufficiency currently requiresopen-heart surgery, by the use of total cardiopulmonary bypass, aorticcross-clamping and cardioplegic cardiac arrest. To certain groups ofpatients, this is particularly hazardous. Elderly patients, patientswith a poor left ventricular function, renal disease, severecalcification of the aorta, and those having previous cardiac surgery orother concomitant diseases would in particular most likely benefit froma less invasive approach, even if repair is not complete.

In view of these drawbacks of previously known treatments, it would bedesirable to provide a minimally invasive approach to treat mitralinsufficiency, i.e., without the need for cardiopulmonary bypass andwithout opening of the chest and heart.

It also would be desirable to provide a reduction of the mitral annulususing only catheter based technology.

It further would be desirable to provide a treatment for mitralinsufficiency that minimizes trauma to a patient's vasculature whileusing catheter based technology.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention toprovide a minimally invasive approach to treat mitral insufficiency,i.e., without the need for cardiopulmonary bypass and without opening ofthe chest and heart.

It is also an object of the present invention to provide a reduction ofthe mitral annulus using only catheter-based technology.

It is another object of the present invention to provide a treatment formitral insufficiency that minimizes trauma to a patient's vasculaturewhile using catheter based technology.

These and other objects of the present invention are achieved byproviding a device for treatment of mitral insufficiency, whereby thecircumference of the mitral valve annulus is reduced when the device isdeployed and/or actuated in at least a portion of the coronary sinus.

The device in accordance with principles of the present invention maycomprise one or more components suitable for deployment in the coronarysinus and adjoining coronary veins. The device may be configured to bendin-situ to apply a compressive load to the mitral valve annulus with orwithout a length change, or may include multiple components that aredrawn or contracted towards one another to reduce the circumference ofthe mitral valve annulus. Any of a number of types of anchors may beused to engage the surrounding vein and tissue, including hooks, barbs,flanges, partial or completely through-wall tee structures, orbiological anchoring. Where multiple components are provided, reductionof the mitral valve annulus may be accomplished during initialdeployment of the device, or by biological actuation during subsequentin-dwelling of the device.

In one embodiment comprising multiple components, the device comprisesproximal and distal stent sections, wherein the proximal stent sectioncomprises a deployable flange. The stent sections are delivered into thecoronary sinus in a contracted state, and then are deployed within thecoronary venous vasculature so that the flange engages the coronarysinus ostium. A cinch mechanism, comprising, for example, a plurality ofwires and eyelets, is provided to reduce the distance between proximaland distal stent sections, thereby reducing the circumference of themitral valve annulus.

In an alternative embodiment, the distal stent is replaced by orincludes a suitably-shaped distal anchor that is disposed within orthrough the left ventricular myocardium. The distal anchor may be in theform of a Tee-shape or barbed section, and engages the ventricularmyocardium, or extends into the left ventricle, to provide a distalfixation point. As in the preceding embodiment, a cinch mechanism isprovided to shorten a structure, such as a wire, that extends betweenthe proximal stent and the distal anchor. The distal anchor may be usedalone or in conjunction with the proximal flange of the precedingembodiment.

In a further alternative embodiment, a balloon catheter is used whereina balloon in fluid communication with a lumen of the catheter comprisesa predetermined deployed shape. A stent, which may be compressed ontothe balloon in a contracted state, then is plastically deformed by theballoon within the coronary sinus, and the stent substantially conformsto the predetermined shape of the balloon in a deployed state. Theballoon preferably comprises a convex shape, so that the stent willassume the convex shape of the balloon and bend the coronary sinusaccordingly. The shape of the stent, convex or otherwise, will beconfigured to reduce the circumference of the mitral valve annulus whendeployed in the coronary sinus.

The configuration of cells of the stent also may be varied to encouragethe stent to assume a convex shape upon deployment. For example, oneside of the stent may be configured to expand a greater amount than theother side, thereby imparting a convex curvature upon the stent. Tofacilitate proper positioning of the stent within the coronary sinus, anintravascular ultrasound transducer or radiopaque marker bands may beused to align the correct side of the stent adjacent the mitral valveannulus.

In a yet further embodiment, the proximal and distal stent sections aredirectly coupled to one another by a central section, so that expansionof the central section causes the proximal and distal stent sections tobe drawn together. In this embodiment, however, the central sectionincludes one or more biodegradable structures, such as biodegradablesutures, that retain the central section in its contracted state untilthe vessel endothelium has overgrown a portion of the proximal anddistal stent sections, thereby providing biological anchoring of theproximal and distal stent sections. After the proximal and distal stentsections have become endothelialized, the biodegradable structuredegrades, releasing the central section and enabling it to expand. Thecentral section thereby applies a tensile load to the proximal anddistal stent sections, causing a reduction in the circumference of themitral valve annulus.

A yet further alternative embodiment comprises a series of linkedsegments that are capable of relative rotational and telescopingmovement. In a preferred embodiment, each segment includes a ballelement that couples to a socket element on an adjacent segment. Theball and socket connections permit the segments of the device to becomeangled relative to one another so that the device is capable of assuminga three-dimensional curvature. A cinch wire extends through a passage inthe segments and permits the device to be cinched rigidly into apredetermined shape. Some segments also may include telescoping jointsthat permit the overall length of the device to be reduced uponactuation of the cinch wire. The cinch wire may include either a lockingmechanism attached to the cinch wire or alternatively may includestriations on the contacting ball and socket surfaces that permit thesegments to rigidly engage one another when cinched.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments, in which:

FIG. 1 is a cross-sectional view of a part of a heart;

FIGS. 2-3 are schematic views of a first embodiment according to thepresent invention;

FIGS. 4-6 are schematic views illustrating an instrument that may beused when positioning the device of FIGS. 2-3 in the coronary sinus;

FIG. 7 is a partial, enlarged view of the first embodiment shown in FIG.2;

FIGS. 8-9 are schematic views illustrating the positioning of the deviceof FIGS. 2-3 in the coronary sinus;

FIGS. 10-11 are schematic views illustrating the positioning of a solidU-shaped wire within the coronary sinus;

FIGS. 12A-12D illustrate an alternative embodiment comprising adeployable flange coupled to the proximal stent section;

FIGS. 13A-13B illustrate deployment and actuation of the device of FIGS.12A-12C;

FIGS. 14A-14C illustrate an alternative embodiment of the device of thepresent invention having a distal anchor;

FIGS. 15A-15B illustrate deployment and, actuation of the device ofFIGS. 14A-14C;

FIGS. 16A-16B illustrate another alternative embodiment of the device ofthe present invention comprising a balloon-expandable device that isdeployed to a curved shape;

FIGS. 17A-17B illustrate a balloon that deploys to a predeterminedcurved shape;

FIGS. 18A-18C are perspective and side views of a further alternativeembodiment of a device of the present invention;

FIGS. 19A-19D illustrate deployment of the device depicted in FIGS.18A-18B; and

FIGS. 20-22 illustrate a still further alternative embodiment of thepresent invention comprising a plurality of interconnected segments anddeployment thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention takes advantage of the position of the coronarysinus being close to the mitral annulus. This makes repair possible bythe use of current catheter-guided techniques by deploying one elementin the coronary venous vasculature that applies a load to, and reshapes,the adjacent posterior portion of the mitral annulus.

The coronary veins drain blood from the myocardium to the right atrium.The smaller veins drain blood directly into the atrial cavity, and thelarger veins accompany the major arteries and run into the coronarysinus which substantially encircles the mitral orifice and annulus. Thecoronary sinus runs in the posterior atrioventricular groove, lying inthe fatty tissue between the left atrial wall and the ventricularmyocardium, before draining into the right atrium between the atrialseptum and the post-Eustachian sinus.

FIG. 1 is a cross-sectional view through the heart area of posterioratrioventricular groove 1, which is filled with fatty tissue. It showsposterior leaflet 2 of the mitral valve and adjoining parts 3, 4 of theatrial myocardium and the ventricular myocardium. Coronary sinus 5 isshown close to mitral annulus 6 and behind attachment 7 of posteriorleaflet 2. Since coronary sinus 5 substantially encircles mitral annulus6, a reduction of the radius of curvature of bent coronary sinus 5 alsowill result in a diameter and circumference reduction of mitral annulus6.

In an adult, the course of coronary sinus 5 may approach within 5-15 mmof the medial attachment of posterior leaflet 2 of the mitral valve.Preliminary measurements performed at autopsies of adults of normalweight show similar results, with a distance of 5.3+/31 0.6 mm at themedial attachment and about 10 mm at the lateral aspect of posteriorleaflet 2. The circumference of coronary sinus 5 was 18.3+/−2.9 mm atits ostium (giving a sinus diameter of the septal aspect of theposterior leaflet of 5.8+/31 0.9 mm) and 9.7+/−0.6 mm along the lateralaspect of posterior leaflet 2 (corresponding to a sinus diameter of3.1+/31 0.2 mm).

In accordance with the principles of the present invention, devices andmethods for treating mitral insufficiency are provided, wherein thecircumference of the mitral valve annulus is reduced when the device isdeployed and/or actuated in at least a portion of the coronary sinus.

Devices constructed in accordance with principles of the presentinvention may comprise one or more components suitable for deployment inthe coronary sinus and adjoining coronary veins. The device may beconfigured to bend in-situ to apply a compressive load to the mitralvalve annulus with or without a length change, or may include multiplecomponents that are drawn or contracted towards one another to reducethe circumference of the mitral valve annulus. Any of a number of typesof anchors may be used to engage the surrounding vein and tissue,including hooks, barbs, flanges, partial or completely through-wall teestructures, or biological anchoring. Where multiple components areprovided, reduction of the mitral valve annulus may be accomplishedduring initial deployment of the device, or by biological actuationduring subsequent in-dwelling of the device.

With respect to FIGS. 2 and 3, a device that experiences shorteningduring deployment is described as comprising an elongate body 8 made ofmemory metal, e.g. Nitinol, or other similar material which has a memoryof an original shape, illustrated in FIG. 3, and which can betemporarily forced into another shape, illustrated in FIG. 2. Elongatebody 8 comprises one, two or more memory metal strings 9 of helical orother shape so as to fit together and be able of to permit the movementsdescribed below. Along elongate body 8, plurality of hooks 10 arefastened so as to extend radially out therefrom. Hooks 10 are covered bya cover sheath 11 in FIG. 2.

Elongate body 8 is forced into a stretched or extended state by means ofstabilizing instrument 12 shown in FIG. 4. Instrument 12 has two arms 13at distal end 14 of rod 15 and locking means 16 at proximal end of rod15. The distance between the ends of rod 15 corresponds to the desiredlength of elongate body 8 when being inserted into coronary sinus 5.

Arms 13 are free to move between the position shown in FIG. 4 and aposition in alignment with rod 15, as shown in FIG. 6. Locking means 16has two locking knobs 17, which are pressed radially outwards from rod15 by two spring blades 18. Thus, elongated body 8 can be pushed overrod 15 of stabilizing instrument 12, then stretched between arms 13 andknobs 17, and finally locked in its stretched state on stabilizinginstrument 12 between arms 13 and knobs 17, as illustrated in FIG. 5.

Rod 15 may be a metal wire which is relatively stiff between distal end14 and locking means 16 but still so bendable that it will follow theshape of coronary sinus 5. Proximally of locking means 16 the metal wireof stabilizing instrument 11 is more pliable to be able to easily followthe bends of the veins.

The above-described elongate body 8 is positioned in the coronary sinus5 in the following way:

An introduction sheath (not shown) of synthetic material may be used toget access to the venous system. Having reached access to the venoussystem, a long guiding wire (not shown) of metal is advanced through theintroduction sheath and via the venous system to coronary sinus 5. Thisguiding wire is provided with X-ray distance markers so that theposition of the guiding wire in coronary sinus 5 may be monitored.

Elongate body 8 is locked onto stabilizing instrument 12, as shown inFIG. 5, and introduced into long cover sheath 11 of synthetic material.This aggregate is then pushed through the introduction sheath and thevenous system to coronary sinus 5 riding on the guiding wire. Afterexact positioning of elongate body 8 in coronary sinus 5, as illustratedin FIG. 8 where mitral valve 19 is shown having central gap 20, coversheath 11 is retracted to expose elongate body 8 within coronary sinus5. This maneuver allows hooks 10 on elongate body 8 to dig into thewalls of coronary sinus 5 and into the heart. Elongate body 8 is stilllocked on to stabilizing instrument 12 such that hooks 10 engage thewalls of coronary sinus 5 in the stretched or extended state of elongatebody 8.

Catheter 12, shown in FIG. 6, is pushed forward on the guiding wire androd 15, to release elongate body 8 from locking means 16 by pressingspring blades 18 toward rod 15. This movement releases knobs 17 as wellas arms 13 from engagement with elongate body 8, which contractselongate body 8 as illustrated in FIG. 9, thereby shortening the radiusof curvature of coronary sinus 5. As a result, mitral valve annulus 6shrinks moving the posterior part thereof forward (shown by arrows inFIG. 9). This movement reduces the circumference of mitral valve annulus6 and thereby closes central gap 20.

FIG. 7 illustrates a part of an arrangement of wires 9 and hooks 10along a peripheral part of elongate body 8, whereby elongate body 8 willbe asymmetrically contracted resulting in a bending thereof wheninterconnecting parts 13 of at least some of hooks 10 are shortened toan original shape.

FIGS. 10 and 11 illustrate an alternative embodiment of an elongate body8′ which does not experience shortening during deployment. Elongate body8′ comprises a solid wire in the shape of an open U-shaped ring thatwill engage the wall of coronary sinus 5 most adjacent to mitral valveannulus 6 when inserted into coronary sinus 5. Elongate body 8′ consistsof a memory metal material which when reverting to its original shapewill bend as illustrated in FIG. 11. The return of open ring 8′ to itsoriginal shape may be initiated in several ways, as is obvious to oneskilled in the art.

Further embodiments comprising two or more stent sections that arecoupled by a system of wires and eyelets are described in co-pendingU.S. patent application Ser. No. 09/775,677 (“the '677 application”),filed Feb. 5, 2001, now U.S. patent application Publication No.2001/0018611, which is incorporated herein by reference. In theembodiments described therein, individual proximal and distal stents arefirst deployed in the coronary sinus, and a cinch mechanism,illustratively comprising a wire and eyelets, is used to draw theproximal and distal stent sections towards one another, thereby reducingthe circumference of the mitral valve annulus.

Referring now to FIGS. 12, a further alternative embodiment isdescribed, wherein the proximal stent section includes a flange that canbe deployed to abut against the coronary ostium. Apparatus 56 comprisesdevice 58 disposed within delivery sheath 60. Device 58 comprisesproximal stent section 62 joined to distal stent section 64 via wire 66and cinch mechanism 67. Proximal and distal stent sections 62 and 64illustratively are self-expanding stents, but alternatively may compriseballoon expandable stents, coiled-sheet stents, or other type of stent.

Stents 62 and 64 are disposed within delivery sheath 60 with a distalend of push tube 68 contacting the proximal end of proximal stentsection 62. Proximal stent section 62 comprises deployable flange 69.Deployable flange 69 is initially constrained within delivery sheath 60,as shown in FIG. 12A, and preferably comprises a shape memory material,e.g., Nitinol, so that flange 69 self-deploys to a predetermined shapeupon retraction of delivery sheath 60.

Wire 66 and cinch mechanism 67 may comprise a combination of wires andeyelets as described in accordance with any of the embodiments in the'677 application, or any other arrangement that permits the wire to betightened and locked into position, as will be apparent to one ofordinary skill. Wire 66 includes a proximal portion that remains outsideof the patient's vessel for manipulation by a physician, and isconfigured to reduce the distance between proximal and distal stentsections 62 and 64.

Apparatus 56 is navigated through the patient's vasculature with stents62 and 64 in the contracted state and into coronary sinus C. The distalend of sheath 60 is disposed, under fluoroscopic guidance, at a suitableposition within the coronary sinus, great cardiac vein, or adjacentvein. Push tube 68 is then urged distally to eject distal stent section64 from within delivery sheath 60, thereby permitting distal stentsection 64 to self-expand into engagement with the vessel wall, as shownin FIG. 12B.

Delivery sheath 60 is then withdrawn proximally, under fluoroscopicguidance, until proximal stent 62 is situated extending from thecoronary sinus. Push tube 68 is then held stationary while sheath 60 isfurther retracted, thus releasing proximal stent section 62. Oncereleased from delivery sheath 60, proximal stent section 62 expands intoengagement with the wall of the coronary sinus, and flange 69 abutsagainst the coronary ostium O, as shown in FIG. 12C.

Delivery sheath 60 (and or push tube 68) may then be positioned againstflange 69 of proximal stent section 62, and wire 66 retracted in theproximal direction to draw distal stent section 64 towards proximalstent section 62. As will of course be understood, distal stent section64 is drawn towards proximal stent section 62 under fluoroscopic orother type of guidance, so that the degree of reduction in the mitralvalve annulus may be assessed. As wire 66 is drawn proximally, cinchmechanism 67 prevents distal slipping of the wire. For example, wire 66may include a series of grooves along its length that are successivelycaptured in a V-shaped groove, a pall and ratchet mechanism, or otherwell-known mechanism that permits one-way motion. Catheter 60 and pushtube 68 then may be removed, as shown in FIG. 12D.

Flange 69 may comprise a substantially circular shape-memory member, asillustrated, a plurality of wire members, e.g., manufactured usingNitinol, that self-deploy upon removal of sheath 60 and abut ostium Owhen proximally retracted, or other suitable shape.

Referring to FIG. 13, a preferred method for using apparatus 56 of FIG.12 to close a central gap 72 of mitral valve 70 is described. In FIG.13A, proximal and distal stent sections 62 and 64 are deployed in thecoronary sinus so that flange 69 of proximal stent section 62 engagescoronary ostium O. Distal stent section 64 is disposed at such adistance apart from proximal stent section 62 that the two stentsections apply a compressive force upon mitral valve 70 when wire 66 andcinch 67 are actuated.

In FIG. 13B, cinch 67 is actuated from the proximal end to reduce thedistance between proximal and distal stent section 62 and 64, e.g., asdescribed hereinabove. When wire 66 and cinch mechanism 67 are actuated,distal stent section 64 is pulled in a proximal direction and proximalstent section 62 is pulled in a distal direction until flange 69 abutscoronary ostium O. The reduction in distance between proximal and distalstent sections 62 and 64 reduces the circumference of mitral valveannulus 71 and thereby closes gap 72. Flange 69 provides a secure anchorpoint that prevents further distally-directed movement of proximal stentsection 62, and reduces shear stresses applied to the proximal portionof the coronary sinus.

Referring now to FIGS. 14, a further aspect of the present invention isdescribed, in which the distal stent section of the embodiment of FIGS.12 is replaced with an anchor that is disposed within or through themyocardium. As will be appreciated, this feature of the device of thepresent invention may be used either separately or in conjunction withthe flange feature described hereinabove. Device 90 comprises proximalstent section 92 coupled by wire 94 and cinch mechanism 95 to distalanchor 96. Proximal stent section 92 may include flange 93. Optionalcoil section 98 extends distally from proximal stent section 92 todistal anchor 96, and serves to distribute compressive forces created bywire 94 to a larger area of the venous vessel wall.

Device 90 is loaded into delivery apparatus 100 comprising curved stylet102, push wire 104 and delivery sheath 106. Curved stylet 102 preferablycomprises a shape memory alloy capable of being straightened, butadopting a curved shape when extended beyond a distal end of deliverysheath 106. Curved stylet 102 includes sharpened distal tip 101 capableof piercing the left ventricular myocardium, and is disposed in lumen105 of delivery sheath. Push wire 104 is slidably disposed in lumen 103of curved stylet 102, and may be advanced distally to eject distalanchor 96 into the left ventricular myocardium or the left ventricle.

As depicted in FIG. 14A, distal anchor comprises a Tee-shaped bar towhich wire 94 is coupled. Optional coil section 98 also may be coupledto distal anchor 96, and is contracted around curved stylet 102 whendevice 90 is loaded into delivery sheath 106. Distal anchor 96 isdisposed within lumen 103 of curved stylet so that wire 94 and coilsection 98 exit through lateral slot 107 in the stylet. Push wire 104 isdisposed in lumen 103 of stylet 102 abutting against the proximal faceof distal anchor 96.

In FIG. 14A, device 90 is shown loaded into delivery apparatus 100.Delivery apparatus 100 has been disposed in the coronary sinus usingconventional guidance and visualization techniques. The distal end ofdelivery apparatus 100 is advanced into the coronary venous vasculatureto a desired location, and then stylet 102 is advanced distally beyondthe end of delivery sheath 106, thereby causing the stylet to regain itscurved shape. Further advancement of stylet 102 causes the distal end ofthe stylet to pierce the coronary vein and extend into the leftventricular myocardium. Push rod 104 is then advanced distally to ejectdistal anchor 96 into the myocardium, or within the left ventricle, asshown in FIG. 14B.

Stylet 102 and push wire 104 are then withdrawn, and delivery sheath 106is retracted until the proximal stent section is disposed extending outof the coronary ostium. By selection of the length of wire 94 fedthrough cinch mechanism 95, proximal stent section 92 may be deployedsimply by retracting delivery sheath 106, because distal anchor 96 andwire 94 will prevent further proximal movement of proximal stent section92. In any event, when proximal stent section 92 is released fromdelivery sheath 106, it self-expands to engage the vessel wall whileflange 93 contacts the coronary ostium, as shown in FIG. 14C.

The proximal end of proximal wire 94 extends through lumen 105 ofdelivery sheath 106 and may be manipulated by a physician. As in theprevious embodiment, once the proximal stent section is deployed, wire94 may be pulled proximally, with cinch mechanism 95 taking up anyslack. The distance between distal anchor 96 and proximal stent section92 may therefore be reduced a desired amount, causing a correspondingreduction in the circumference of the mitral valve annulus. Optionalcoil section 98, if present, assists in redistributing the compressiveforces applied by wire 94 to the interior surface of the venous vessel.

Referring to FIGS. 15A and 15B, device 90 of FIGS. 14 is illustrated ina deployed state to treat mitral insufficiency. Flange 93 is deployedabutting coronary ostium O, e.g., within right atrium A. Proximal stentsection 92 and optional coil section 98 are deployed within the coronarysinus and great cardiac vein C. Distal anchor 96 is disposed withinmyocardium M, or alternatively, may extend into the left ventricle oranother suitable region, as will be obvious to those skilled in the art.It should further be appreciated to those skilled in the art that whileanchor 96 is illustrated as a cylindrical bar, it may comprise square,circular or other configurations, e.g., a plurality of barbs.

The proximal end of wire 94 extends through cinch mechanism 95 and ismanipulated to impose tension on wire 94, thereby reducing the distancebetween proximal stent section 92 and distal anchor 96. This in turnreduces the circumference of coronary sinus C accordingly, as shown inFIG. 15B. Upon completion of the procedure, i.e., when gap 72 issufficiently closed, apparatus 100 is removed from the patient's vessel.

Advantageously, the use of distal anchor 96 is expected to reduce theshear stress imposed on coronary sinus C relative to the use of aproximal stent section alone as described for the embodiment of FIGS. 12and 13.

Referring now to FIGS. 16 and 17, another embodiment of a devicesuitable for repairing mitral valve insufficiency is described. In thisembodiment, device 110 comprises a balloon expandable stent 112, whichmay be tapered along its length. Stent 112 is disposed on balloon 114 atthe distal region of balloon catheter 113. Balloon 114 is capable ofassuming a curved shape when inflated. As depicted in FIG. 16A, stent112 and balloon catheter 113 are disposed in the patient's coronarysinus through the coronary ostium.

Once the position of stent 112 is determined, for example, byfluoroscopy, balloon 114 is inflated via to expand balloon 114 to itspredetermined curved shape. Inflation of balloon 114 causes stent 112 tobe plastically deformed in accordance with the predetermined shape ofballoon 114. As will be of course be appreciated, the degree of mitralvalve regurgitation may be monitored during the step of inflatingballoon 114, so that stent 112 applies only so much compressive load onthe mitral valve annulus as is required to reduce the regurgitation to aclinically acceptable level. Catheter 113 is removed from the patient'svessel upon completion of the stenting procedure.

Referring to FIGS. 17A and 17B, the distal region of a balloon cathetersuitable for use in the embodiment of FIGS. 16 is described. Ballooncatheter 113 has proximal and distal ends, and comprises balloon 114,and inflation lumen and guidewire lumens, as is per se known. Inaccordance with the principles of the present invention, balloon 114includes an anchor element 116, such as a strand of wire, affixed to itsinterior surface, so that when the balloon is inflated, it adopts apredetermined shape, as shown in FIG. 17B. Anchor element 116 maycomprise a radiopaque material or radiopaque coating to facilitateproper positioning of stent 112 within coronary sinus C. When balloon114 is deflated, the balloon assumes a straight configuration, shown inFIG. 17A, thus permitting stent 112 to be crimped to its outer surface.

In an alternative embodiment of the device of FIGS. 16-17, anchorelement 116 may be omitted and balloon 114 may be pre-shrunk on oneside, thereby causing the balloon to deploy to the shape depicted inFIG. 17B. In yet another embodiment, the configuration of cells 117 ofstent 112 may be varied to encourage the stent to assume a convex shapeupon deployment. For example, the side of the stent adjacent mitralvalve annulus 71 may expand less than the side of the stent opposing themitral valve annulus, thereby imparting a convex curvature upon thestent, as shown in FIG. 16B.

To ensure proper alignment of stent 112 within the coronary sinus priorto deployment of the stent, an intravascular ultrasound transducer or,alternatively, radiopaque marker bands may be used to align the correctside of the stent adjacent the mitral valve annulus. The use of suchimaging modalities are described, for example, in U.S. patentapplication Ser. No. 09/916,394 (“the '394 application”), now U.S.patent application Publication No. 2002/0019660, which is herebyincorporated by reference in its entirety. Additionally, furthertechniques for providing a curved stent in accordance with methods ofFIGS. 16-17 also are described in the '394 application.

Referring now to FIGS. 18A-19C, another alternative embodiment of thepresent invention is described, in which the device comprises proximaland distal stent sections joined by a central section capable ofundergoing foreshortening. Device 120 comprises proximal stent section122, distal stent section 124 and central section 126. Further inaccordance with the principles of the present invention, device 120includes one or more biodegradable structures 128, such as sutures,disposed on central section 126 to retain that section in the contractedshape for a predetermined period after placement of the device in apatient's vessel. In FIG. 18A, device 120 is depicted with its proximaland distal stent sections radially expanded, but with central section126 restrained in the contracted position. FIG. 18B depicts device 120with all three stent sections contracted as if disposed in a deliverycatheter. FIG. 18C shows all three stent sections fully expanded.

In a preferred embodiment, all three sections are integrally formed froma single shape memory alloy tube, e.g., by laser cutting. The stentsections then are processed, using known techniques, to form aself-expanding unit. Device 120 has a contracted delivery configuration,wherein the device is radially contracted within a delivery sheath, anda deployed expanded configuration, wherein at least the proximal anddistal sections self-expand to engage the interior surface of thecoronary sinus or adjoining veins. Further in accordance with thepresent invention, the biodegradable structures may be designed tobiodegrade simultaneously or at selected intervals.

Unlike the preceding embodiments, which may include either a proximalflange, distal anchor, or both, and which rely upon drawing the proximaland distal stent sections together at the time of deploying the device,this embodiment of the present invention permits the proximal and distalstent sections 122 and 124 to become biologically anchored in the venousvasculature before those sections are drawn together by expansion ofcentral section 126 to impose a compressive load on the mitral valveannulus.

In particular, as depicted in FIGS. 19A-19D, device 120 is loaded intodelivery sheath 121 and positioned within the patient's coronary sinus.The device is then ejected from the delivery sheath, so that theproximal and distal stent sections 122 and 124 radially expand intoengagement with the vessel wall. At the time of deployment, centralsection 126 is retained in a contracted state by biodegradablestructures 128, illustratively biodegradable sutures, e.g., apoly-glycol lactide strand or VICREL suture, offered by Ethicon, Inc.,New Brunswick, N.J., USA.

Over the course of several weeks to months, the proximal and distalstent sections 122 and 124 will endothelialize, i.e., the vesselendothelium will form a layer E that extends through the apertures inthe proximal and distal stent sections and causes those stent sectionsto become biologically anchored to the vessel wall, as depicted in FIG.19C. This phenomenon may be further enhanced by the use of a copperlayer on the proximal and distal stent sections, as this element isknown to cause an aggressive inflammatory reaction. Other techniques forenhancing an inflammatory reaction, such as coatings or layers, will beapparent to those skilled in the art.

Over the course of several weeks to months, and preferably after theproximal and distal stent sections have become anchored in the vessel,biodegradable structures 128 that retain central section 126 in thecontracted state will biodegrade. Eventually, the self-expanding forceof the central section will cause the biodegradable structures to break,and release central section 126 to expand. Because central section 126is designed to shorten as it expands radially, it causes the proximaland distal stent sections 122 and 124 of device 120 to be drawn towardsone another, as shown in FIG. 19D. The compressive force created byexpansion of central section 126 thereby compressively loads, and thusremodels, the mitral valve annulus, as depicted.

As suggested hereinabove, biodegradable structures 128 may be designedto rupture simultaneously, or alternatively, at selected intervals overa prolonged period of several months or more. In this manner,progressive remodeling of the mitral valve annulus may be accomplishedover a gradual period, without additional interventional procedures. Inaddition, because the collateral drainage paths exist for blood enteringthe coronary sinus, it is expected that the device will accomplish itsobjective even if it results in gradual total occlusion of the coronarysinus.

Referring now to FIGS. 20A-20B, another alternative embodiment of thepresent invention is described. In FIG. 20A, apparatus 180 comprises aplurality of interlocking segments 181. Each interlocking segment 181preferably comprises a proximal section having socket 184, a distalsection having ball 182, and a central section 183 extendingtherebetween. Each interlocking segment 181 further comprises lumen 185configured to permit cinch wire 187 to pass through lumen 185. Cinchwire 187 having proximal and distal ends preferably comprises ball 188affixed to the distal end so that ball 188 engages a distalmostinterlocking segment 181 when retracted proximally. The retraction ofcinch wire 187 enables a ball 182 to interlock with a socket 184 of anadjacent segment 181.

Apparatus 180 of FIG. 20A preferably is used in combination withapparatus 190 of FIG. 20B. A preferred use of apparatus 180 and 190 incombination is described in FIG. 22 hereinbelow. Apparatus 190 comprisesproximal ball segment 202, distal ball segment 200, and connectingsegment 204 having a plurality of sockets 205 separated by humps 209.Proximal ball segment 202 comprises proximal and distal ball segments212 and 210, respectively, each having lumens extending therethrough,and hollow rod 211 extending therebetween. Similarly, distal ballsegment 200 comprises proximal and distal balls 208 and 206,respectively, each having lumens extending therethrough, and hollow rod207 extending therebetween. Distal ball 210 of proximal segment 202initially is configured to engage the most proximal socket 205 withinconnecting segment 204, while proximal ball 208 of distal segment 200initially is configured to engage a distalmost socket 205.

Proximal and distal ball segments 202 and 200 are capable of relativerotational and telescoping movement. Such movement may be achieved usinga cinch wire configured to pass through each segment 200 and 202, asshown in FIG. 21A. In FIG. 21A, cinch wire 218 comprises distal ball 220that is larger than a lumen of hollow rod 207 and is configured to abutdistal ball 206 when a proximal end of cinch wire 218 is retractedproximally. Cinch wire 218 preferably is used in combination with pushtube 216 that may stabilize or distally advance proximal segment 202.

By varying the maneuvers of push tube 216 and cinch wire 218, a range oftelescoping and rotational motions between proximal and distal segments202 and 200 may be achieved, as shown in FIG. 21B. In FIG. 21B, a pushforce applied to ball 212 allows ball 210 to overcome the resistiveforces provided by hump 209. As illustrated, the push force applied toball 212 has advanced proximal segment 202 by two sockets relative todistal segment 200. Also, as shown in FIG. 21B, distal segment 200 hasbeen retracted by one socket with respect to proximal segment 202, e.g.,by proximally retracting cinch wire 218. Ball 208 also has been rotatedat an angle, which in turn rotates distal segment 200 with respect toproximal segment 202.

Referring to FIG. 21C, an alternative method for providing relativetelescoping and rotational motion for apparatus 190 of FIG. 20B isdescribed. Apparatus 190 further comprises push tube 216 and wire loop225. Wire loop 225 extends through a lumen within proximal and distalsegments 202 and 200, then loops around the distal end of distal segment200 and back into opening 227 of push tube 216. A physician then maymanipulate a proximal portion of wire loop 225 to provide a range oftelescoping or rotational motions between proximal and distal segments202 and 200. At least one hook or eyelet 231 may be coupled to anexterior surface of connecting segment 204 to serve as a guide for wire225, and to facilitate controlled actuation of proximal and distalsegments 202 and 200.

Referring now to FIG. 22, a combination of apparatus 180 and apparatus190 are used to provide a range of motion within vessel V, e.g., thecoronary sinus. As described hereinabove, the present invention aims totreat mitral insufficiency by shortening the radius of curvature of thecoronary sinus, which in turn applies a compressive force upon themitral valve. In FIG. 22, the combination of apparatus 180 and apparatus190 first may engage a wall of vessel V, e.g., via barbs or hooks (notshown) affixed to apparatus 180 and 190, and then the relativetelescoping or rotational motion of segments may be used to bend vesselV to apply a compressive load on the mitral valve annulus.

In a preferred embodiment, mitral insufficiency apparatus 179 comprisesa proximal and distal section comprising apparatus 180, and a pluralityof sections comprising apparatus 190 disposed therebetween. Cinch wire218 and push tube 216 of FIGS. 21 preferably are used to manipulaterelative rotational and telescopic motion of all of the components. In afirst preferred step, the balls of apparatus 180 are coupled to theirrespective sockets, e.g., by proximally retracting cinch wire 218. Then,in a next step, balls 240 and 250 which connect apparatus 180 toapparatus 190 are rotated within sockets of connective segment 204 toallow apparatus 180 to be angled relative to apparatus 190 by angles.alpha. and .beta., as illustrated in FIG. 22. This in turn applies adesired compressive load on the mitral valve annulus. Then, in a finalstep, the balls of apparatus 190 may be advanced incrementally in alongitudinal direction within sockets 205 of connective segments 204 toreduce distance X. When vessel V is the coronary sinus, reducing thedistance X will apply a compressive force to the mitral valve to treatmitral insufficiency.

While preferred illustrative embodiments of the invention are describedabove, it will be apparent to one skilled in the art that variouschanges and modifications may be made therein without departing from theinvention. The appended claims are intended to cover all such changesand modifications that fall within the true spirit and scope of theinvention.

1. A method of treating dilatation of the mitral valve annulus,comprising: advancing a balloon catheter through a coronary ostium andinto a coronary sinus, the balloon catheter including a balloon disposednear a distal region and a balloon expandable stent mounted on theballoon, wherein the balloon and the stent are in a radially collapsedconfiguration during the advancement, the stent having a lengthextending from a proximal end to a distal end of the stent; positioningthe stent in a desired location in the coronary sinus; inflating theballoon to expand the stent in the coronary sinus; and reducing acircumference of the mitral valve annulus by decreasing the length ofthe stent, thereby bending the coronary sinus.
 2. The method of claim 1,wherein the balloon assumes a predetermined curved shape when inflated.3. The method of claim 1, wherein the stent is tapered along alongitudinal axis.
 4. The method of claim 1, wherein the location of thestent in the coronary sinus is determined using fluoroscopy.
 5. Themethod of claim 1, wherein inflation of the balloon caused the stent tobe plastically deformed.
 6. The method of claim 1, wherein a degree ofmitral valve regurgitation is monitored while inflating the balloon. 7.The method of claim 1, wherein the balloon comprises an anchor elementon one side for causing the balloon to assume a predetermined shape. 8.The method of claim 7, wherein the anchor element is formed of aradiopaque material.
 9. The method of claim 1, wherein the balloon ispreshrunk on one side for causing the balloon to assume a predeterminedshape.
 10. The method of claim 1, wherein the stent expands to a greaterdegree on one side for providing the stent with a curved shape.
 11. Themethod of claim 1, wherein an intravascular ultrasound transducer isused to align the correct side of the stent adjacent the mitral valveannulus.
 12. The method of claim 1, wherein the stent comprises aproximal stent section, a distal stent section, and a central sectionextending between the proximal and distal stent sections.
 13. The methodof claim 12, further comprising expanding the distal stent sectionwithin the coronary sinus before expanding the proximal stent sectionwithin the coronary sinus.
 14. The method of claim 12, wherein thecentral section is retained in a contracted state by a biodegradablestructure.
 15. The method of claim 14, wherein the biodegradablestructure comprises a suture.
 16. A method of treating dilatation of themitral valve annulus, comprising: advancing a balloon catheter through acoronary ostium and into a coronary sinus, the balloon catheterincluding a balloon disposed near a distal region, the balloon beingformed to expand to a predetermined curved shape, the balloon catheterfurther including a plastically deformable stent mounted on the balloon,wherein the balloon and the stent are in a radially collapsedconfiguration during the advancement, the stent having a lengthextending from a proximal end to a distal end of the stent; positioningthe stent in a desired location in the coronary sinus under fluoroscopy;inflating the balloon while monitoring mitral regurgitation toplastically expand the stent into a curved shape; and reducing acircumference of the mitral valve annulus by decreasing the length ofthe stent, thereby causing the coronary sinus to bend.
 17. The method ofclaim 16, wherein the stent comprises a proximal stent section, a distalstent section, and a central section extending between the proximal anddistal stent sections.
 18. The method of claim 17, further comprisingexpanding the distal stent section within the coronary sinus beforeexpanding the proximal stent section within the coronary sinus.
 19. Themethod of claim 17, wherein the central section is retained in acontracted state by a biodegradable structure.
 20. The method of claim19, wherein the biodegradable structure comprises a suture.
 21. A methodof treating dilatation of a mitral valve annulus, comprising: advancinga balloon catheter into a coronary sinus, the balloon catheter includinga balloon disposed near a distal region and a balloon expandable implantmounted on the balloon, wherein the balloon and the implant are in aradially collapsed configuration during the advancing, the implanthaving a length extending from a proximal end to a distal end of theimplant; positioning the implant in a desired location in the coronarysinus; inflating the balloon to expand the implant in the coronarysinus; and reshaping the mitral valve annulus by decreasing the lengthof the implant, thereby altering a shape of the coronary sinus andreducing a circumference of the mitral valve annulus.
 22. The method ofclaim 21, wherein the implant comprises a proximal implant section, adistal implant section, and a central section extending between theproximal and distal implant sections.
 23. The method of claim 22,further comprising expanding the distal implant section within thecoronary sinus before expanding the proximal implant section within thecoronary sinus.
 24. The method of claim 22, wherein the central sectionis retained in a contracted state by a biodegradable structure.
 25. Themethod of claim 24, wherein the biodegradable structure comprises asuture.
 26. A method of treating dilatation of a mitral valve annulus,comprising: advancing a catheter into a coronary sinus, the cathetercarrying an expandable implant that is in a radially collapsedconfiguration during the advancing, the implant having a lengthextending from a proximal end to a distal end of the implant;positioning the implant in a desired location in the coronary sinus;expanding the implant in the coronary sinus; and altering a shape of thecoronary sinus by decreasing the length of the implant, thereby reducinga circumference of the mitral valve annulus.
 27. The method of claim 26,wherein the implant comprises a proximal implant section, a distalimplant section, and a central section extending between the proximaland distal implant sections.
 28. The method of claim 27, furthercomprising expanding the distal implant section within the coronarysinus before expanding the proximal implant section within the coronarysinus.
 29. The method of claim 27, wherein the central section isretained in a contracted state by a biodegradable structure.
 30. Themethod of claim 29, wherein the biodegradable structure comprises asuture.
 31. A method of treating dilatation of a mitral valve annulus,comprising: advancing a catheter into a coronary sinus, the cathetercarrying an expandable implant that is in a radially collapsedconfiguration during the advancing, the implant having a lengthextending from a proximal portion to a distal portion of the implant;positioning the implant in the coronary sinus; expanding the implant inthe coronary sinus; and changing a shape of the mitral valve annulus bydecreasing the length of the implant, thereby altering a shape of thecoronary sinus, wherein the implant comprises a proximal implantsection, a distal implant section, and a central section extendingbetween the proximal and distal implant sections, the central sectionbeing retained in a contracted state during the advancing by abiodegradable structure, wherein the central section is retained in thecontracted state by the biodegradable structure after expansion, withinthe coronary sinus, of both the proximal and distal implant sections,and the central section is configured to, upon expansion, draw theproximal and distal implant sections together and to decrease the lengthof the implant.
 32. The method of claim 31, wherein the biodegradablestructure comprises a suture.